Guide and hold-down assembly for machines for abrading the surface of flexible materials



May 28, 1 7 H D TEETZ SR 2,793,475

GUIDE AND HoLo-150m 1 ASSEMBLZY FOR MACHINES FOR ABRADING THE SURFACE OF FLEXIBLE MATERIALS Filed Nov. 18, 195.3

one, K/Lau/e/v CARLSOM ATTORNEYS GUIDE AND HOLD-DOWN ASSEMBLY FOR MA- CHINES FUR AHRADING THE SURFACE OF FLEXHBLE MATERIALS Application November 18, 1953, Serial No. 392,935

3 Claims. (CI. 51-78) This invention relates to apparatus which is auxiliary to apparatus for abrading the surface of flexible materials, to reduce such material to uniform thickness or for other purposes. More particularly the apparatus is to guide and hold down on a feed roll a sheet or length of material being fed to means for treating it such for example as an abrasive roll or drum travelling at a higher rate of speed than the feed roll.

in recent years it has been found advantageous to treat a wide variety of materials by the passing of them over a feed roll to an abrading surface, such as a drum covered with a sheet of sandpaper and rotated at high speed. Great difiiculty has been encountered particularly in the treatment of flexible materials due to the fact that the trailing edge of the sheet or length of material tends to snap forwardly as soon as it is freed from the bite between a feed roll and a pinch roll or equivalent usually employed in conjunction with the feed roll, with the result that the trailing edge often doubles over against the abrasive roll and is cut and scored too much or too little in passing between the feed roll and the surface of the abrading roll and is thus damaged and becomes waste.

Further ditficulty has been encountered in the treatment of flexible materials different portions of which are initially of different thicknesses. Prior art guides have not satisfactorily held down against the feed roll portions of the sheet or length of material adjoining high spots in the material.

Accordingly it is an object of the invention to provide improved guide and hold-down apparatus which may either be installed as an attachment on previously manufactured abrading equipment, or incorporated as an adjunct during the manufacture of such machines.

Another object of the invention is to provide means which will effectively prevent the snapping forward of the trailing end of flexible materials being abraded and thus avoid the damage and waste often resulting from such action.

Another object of the invention is to provide means for more eifectively holding down a length or sheet of material on the feed roll throughout its entire width.

Other objects of the invention will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, arrangements of parts, and in the several steps and relation and order of each of said steps to one or more of the others thereof, all as will be pointed out in the following description, and the scope of the application of which will be indicated in the following claims.

The invention will best beunderstood if the following description is read in connection with the drawings, in which,

Figure l is an end view illustrating schematically the doubling over of the trailing edge of a sheet or length of material being abraded in a known abrading machine, after the trailing edge of the sheet or length of material has passed the pinch roll;

itcd States Patent Figure 2 is an end elevational View of one embodiment of the invention shown applied to a known combination of abrading roll, feed roll and pivoted pinch roll;

Figure 3 is a plan View of the assembly of Figure 2, broken away and showning only one end portion of a combination of abrading, feed and pinch rolls and apparatus embodying the invention applied thereto, said apparatus being duplicated at opposite ends of said combination of rolls;

Figure 4 is a fragmentary perspective view, of the guide and hold-down means illustrated in Figures. 2 and 3, adapted for mounting on the pinch roll shaft beyond the ends of the pinch roll; and

Figure 5 is a view similar to Figure 4 but showing guide and hold-down means comprising a number of separate members operative individually.

Abrading machines comprising the combination of abrading drum 1t), feed roll 12, and pinch roll 14 shown in Figure 1, are well known and such machines are disclosed in Patents No. 1,975,349, October 2, 1934; No. 2,076,193, April 6, 1937; No. 2,253,558, August 26, 1941; and No. 2,253,559 August 26, 1941; issued to George M. Curtin. In such machines a sheet or length of material comprising a skin or length of fabric or other flexible material is led between feed roll 12 and pinch roll 14 before being engaged between the feed roll 12 and the roll 16 having the abrading surface which, as illustrated in the aforesaid patents, may be a sheet of sandpaper. In such machines the abrading roll usually rotates at a considerably higher speed than the feed roll and trouble has been encountered due to the fact that the trailing edge of flexible material being treated is snapped forward by the pull of the abrasive roll when it is free from engagement between the feed roll and pinch roll, and often doubles over with the result that it is damaged in passing in doubled over condition between the feed roll and the abrading roll and thus becomes waste. This is particularly the case in the treatment of skins and other material the trailing end of which becomes narrower adjacent the trailing edge and is thus particularly subject to being snapped forward and doubling over. A length of ma terial m the trailing edge of which has been doubled over as at D is shown in Figure 1.

In Figure 2 apparatus comprising the invention is shown added to the combination of abrading roll, feed roll and pinch roll shown in Figure 1. In Figure 2 previously known means for pivotally supporting the pinch roll 14 is also shown, comprising an arm 16 such as is employed at each end of the pinch roll having the bearing 17 for receiving an end of the pinch roll shaft 18, said arm 16 being pivotally mounted by pivot 20 on bracket 22 which is duplicated at the opposite end of the prior art machines. The elevation of pinch roll shaft 18 may be adjusted by adjustment of the adjusting screw 24 which extends through arm 16 into contact with the upper surface 26 of said brackets 22.

To the above described known assembly I provide a curved guide and hold-down member 28 and means for supporting it so that its leading edge 28a will tend to contact a sheet or length of material on the feed roll in close proximity to the bite between feed roll 12 and abrading roll 10.

Member 28 is shown projecting from a cross bar 30 having at its ends reaiwardly extending brackets 32 having respectively the aligned openings 34 by which said brackets may be loosely hung on the respective ends of the pinch roll shaft 18 beyond the ends of the pinch roll 14. Brackets 32 are secured to cross bar 30 by screws s. The assembly comprising cross bar 30 and guide and hold-down member 28 may pivot freely around shaft 18 irrespective of whether or not said shaft. rotates with the roll 14 or is stationary with roll 14 rotating around it.

In order to provide limits to the oscillatory movement of the guide and hold-down assembly the brackets 32 may be formed as shown in Figure 2 with the two projecting, parallel, spaced arms 36 and 38, with the adjustable contact screws 40 and 42 extending through said arms respectively toward one another on either side of a stop member 44 secured by screw 46 onto the fiat top portion 48 of said arm 16.

The guide and hold-down member 28 may be somewhat curved as illustrated in the drawings and preferably has its forward end portion tapered so that its leading edge 28a can extend close to the bite between the feed roll 12 and the abrading roll 10. Since the center of gravity of the guide and hold-:down assembly is well forward of its bearings 34 it will tend to pivot clockwise to bring the leading edge 28a into contact with the surface of material passing over the feed roll adjacent of contact between member 28 and the sheet or length of material extending the full width of said sheet or length of material.

It will thus be seen that there has been provided by this invention an apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted V as illustrative and not in a limiting sense.

to the bite between the feed roll and the abrading roll.

Preferably member 28 extends substantially from the periphery of the pinch roll 14 to the bite between the feed roll 12 and the abrading roll 10 and thus serves to intercept the trailing edge portion of a sheet or length of material as soon as it is freed from engagement between the pinch roll 14 and the feed roll 12 and prevents it from snapping forward. The leading edge 28a of member 28 continues to hold the sheet or length of material against the surface of the feed roll until the trailing edge of the material is about to enter the bite between the feed roll 12 and abrading roll 10 when there is not enough length of the material left above the bite between rolls 10 and 12 to permit it to fold over, and by that time the distance between the peripheries of rolls 10 and 12 is so slight that any such folding over is unlikely.

In Figure 5 a modification of the guide and hold-down assembly is shown in which brackets 32a are employed which may be similar to brackets 32 except for having the brackets 50 to receive the ends of a cross rod 52 which in this embodiment of the invention takes the place of the cross bar 30, and on which a plurality of guide and hold-down members 28a are supported each independently rotatable around cross rod 52. Since members 28a are of narrow width and of light weight compared with the mass of a unitary member such as 28, spring means 54 are provided for increasing the effective weight of said members 2811. wound around cross shaft 52 between the spaced sleeves 56, 58 by which'said members 28a are mounted for rotation around on cross shaft 52, with one end 54a of each spring secured to said cross shaft and the other end 54!; projecting against the member 28a with which it i is associated.

It will be understood that apart from or supplementing the force of gravity member 28 may be controlled, to give any tension that may be desired on material passing through the device, as for example, by adjustment of the position of arm means 16 by adjusting screws 24.

The brackets 32a have therein respectively the aligned openings 34a by which the bracket members may be loosely supported upon a cross shaft of the abrading machine to which they are applied, or of which they form a part, such for example as the pinch roll shaft 18, as has been described above. The individual members 28a have the advantage over a continuous guide and holddown membersuch as 28 of being able to maintain local portions of the sheet or length of material passing over the feed roll in closer contact with the feed roll. Each member 28a rests on thehigh spot of the particular portion of the sheet or length of material along the line of For this purpose the springs 54 may be contact between said member 28a and said portion whereas the closest approach of member 28 to the sheet or length of material being processed is determined by the highest spot or point of greatest thickness along the line What I claim is: I,

1. In a machine for abrading the surface of flexible materials the combination of a rotary abrading roll, a feed roll coactive-with the abrading roll to feed the material to the abrading roll, a pinch roll coactive with the feed roll to feed the material to the abrading roll, pivoted arms providing journals for the pinch roll shaft, means for adjusting said arms to regulate the position of said pinch roll relative to the feed roll, and an assembly for holding down work being fed over the feed roll to the abrasive roll mounted on said pinch roll shaft for rotation around said shaft, said assembly comprising a cross rod, brackets extending rearwardly from said cross rod for hanging said brackets on the opposite ends respectively of said pinch roll shaft, and a number of guide and hold-down members rotatably mounted on said cross rod and projecting forwardly and downwardly from said cross rod and extending substantially to the bite between the feed roll and the abrading roll.

2. In a machine for abrading the surface of flexible materials the combination of a rotary abrading roll, a feed roll coactive with the abrading roll to feed the material to the abrading roll, a pinch roll coactive with the feed roll to feed the material to the abrading roll, pivoted arms providing journals for the pinch roll shaft, stop members on said pivoted arms respectively, means for adjusting said arms to regulate the position of said pinch roll relation to the feed roll, and an assembly for holding down work being fed over the feed roll to the abrasive roll mounted on said pinch roll shaft for rotation around said shaft, said assembly comprising a pair of brackets each bracket comprising two parallel arms projecting on opposite sides of one of said stop members, and adjustable contact screws extending through said arms respectively toward said stop member to provide limits to the swinging movement of said assembly around said pinch roll shaft.

3. The device claimed in claim 1 including spring means individual to said guide and hold-down members respectively, acting to swing said members downwardly around said rod.

References Cited in the file of this patent UNITED STATES PATENTS 636,970 Feix Nov. 14, 1899 908,115 Maze Dec. 29, 1908 954,376 Buss Apr. 5, 1910 1,208,116 Feix Dec. 12, 1916 1,566,358 White Dec. 22, 1925 1,933,665 Duplessis Nov. 7, 1933 1,952,634 ,Spry Mar. 27, 1934 2,170,901 Jorgensen Aug. 29, 1939 2,278,138 Paardecarnp Mar. 31, 1942 2,305,879 Leach Dec. 22, 1942 FOREIGN PATENTS 39,648 Norway Sept. 1, 1924 

